A conventional air conditioning system for a motor vehicle of this kind, for example, as disclosed in Japanese Patent Publication S62-299420, comprises a pyroelectric temperature sensor (i.e. an infrared temperature sensor) for detecting surface temperature of occupant's clothing as a no-contact type temperature sensor, an air conditioning unit for blowing conditioned air into a passenger compartment of a motor vehicle, and an electronic control unit for calculating a target blowing air temperature (which is temperature of the air blown into the passenger compartment from the air conditioning unit) based on the temperature detected by the pyroelectric temperature sensor and controlling the air conditioning unit so that the blowing air temperature becomes close to the target blowing air temperature.
In the above conventional system, when a passenger gets into the passenger compartment of the motor vehicle during a winter period in which an ambient (outside) temperature is low, the electronic control unit calculates the target blowing air temperature at a higher value than an ordinal temperature in the other cases, because the temperature of the passenger's clothing is lower due to the outside low temperature. And thereby, the blowing air temperature from the air conditioning unit can be set at a higher value in response to the outside low temperature, shortly after the passenger gets in the motor vehicle.
On the other hand, when a passenger gets into the passenger compartment of the motor vehicle during a summer period in which an ambient (outside) temperature is high, the electronic control unit calculates the target blowing air temperature at a lower value than an ordinal temperature in the other cases, because the temperature of the passenger's clothing is higher due to the outside high temperature. And thereby, the blowing air temperature from the air conditioning unit can be set at a lower value in response to the outside high temperature, shortly after the passenger gets in the motor vehicle, even in the case that an operational condition of the air conditioning unit is in a normal operation mode shortly before the passenger gets in the motor vehicle.
According to researches of the inventors of this invention, with regard to comfortable feeling which the passenger gets by the blowing air from the air conditioning unit shortly after he gets into the motor vehicle, it was found out that there are following two problems.
According to the above conventional system, the blowing air temperature can be adjusted at the higher value than the ordinal temperature during the winter season, in accordance with the surface temperature of the passenger's clothing. However, the target blowing air temperature is decreased by the electronic control unit within a short period, because heat capacity of the clothing is generally small and thereby the temperature of the clothing is increased in the short period due to the inside temperature of the passenger compartment. The temperature of the air blowing out of the air conditioning unit is decreased, before the passenger feels “warm”. As a result, the above conventional system can not sufficiently give a comfortable feeling to the passenger by the warm air, during a period shortly after the passenger gets into the motor vehicle.
On the other hand, the blowing air temperature can be adjusted at the lower value than the ordinal temperature during the summer season. However, the target blowing air temperature is increased by the electronic control unit within a short period, because the temperature of the clothing is decreased in the short period due to the inside temperature of the passenger compartment. The temperature of the air blowing out of the air conditioning unit is increased, before the passenger feels “cool”. As a result, the above conventional system can not sufficiently give a comfortable feeling to the passenger by the cool air, either, during a period shortly after the passenger gets into the motor vehicle.